Carrie Brownstein, a founder of Sleater-Kinney, the most accomplished trio of Northwest rockers since Nirvana, is lying in the mud by the Sandy River, cursing and moaning in pain. Half a minute ago, the guitarist/vocalist/songwriter was concentrating on our cell-phone interview while strolling with her dog through some Forest Service land located about 10 miles east of Portland, on the way to Mount Hood. Suddenly, her dog leapt across a flooded rivulet, knocking her off her feet as if she were a football player being clipped — except that, as a doctor points out later in the emergency room, "I wasn’t wearing any pads."

Sitting up in the mud and trying to collect herself, Brownstein jokes, "I feel like we’re in one of those movies where you’re my only lifeline and you have to use GPS signals to get the cops out to me." In the end, she finds her own way home, and then, on the advice of her doctor, goes to the hospital, where concussion is ruled out and Vicodin prescribed. When I reach her again the next morning, she’s still "in a lot of pain" and is still amazed at the incident: "It was very . . . very . . . very bizarre."

Even so, the lesson is commonplace: shit happens, expect the unexpected, and when you’re alone in the wilderness, expect the unexpected shit to be a hell of a lot worse. In a coincidence that’s also very, very, very bizarre, that’s the lesson of Sleater-Kinney’s new The Woods (Sub Pop). The difference is that the disc is as profound as raw rock and roll gets, a reminder of how art can reinvigorate tragic truths that mundane adulthood tends to turn into comic cliché.

Carrie Brownstein, fellow Sleater-Kinney frontwoman Corin Tucker, and drummer Janet Weiss get there by escaping their own clichés. At least one critic has already quipped that the three women are going through a seventh-album itch, launching themselves as far into the musical wilderness as they can go without severing their ties to home. Recorded for the first time outside the Northwest (in woodsy upstate New York), for the biggest indie label they’ve ever signed with (Sub Pop), and with a producer they’ve never used before (Dave Fridmann, best known for his work with Flaming Lips and Mercury Rev), The Woods dismantles the band’s classic post-punk style with the tools of pre-punk hard rock: think of the Who’s Live at Leeds, LedZeppelin’s Houses of the Holy, Jimi Hendrix’s Axis Bold As Love.

Brownstein admits that The Woods "is inspired by all that stuff. But I don’t think it’s rehashing it in a way that’s just retrospective or boring. I think that there’re plenty of bands that come along that you’re like, ‘God, they do sound like something, they’re reminding me of this band or that band, but they’re making it feel absolutely new.’ That’s why I think the White Stripes are a million times better than Interpol. The White Stripes made it feel brand new, even though it was blues riffs, you know? But Interpol just makes me think that Ian Curtis should be getting royalties. There’s that line [on The Woods’ "Entertain"] ‘You come around sounding 1972/Where’s the black and blue?’ Where’s the essence of it?"

Sleater-Kinney don’t shy away from their own black and blue in a makeover that can be as brutal as their music. The group’s trademark acerbic tunings, intertwined vocals, and complex riffs are still there, yet they’re simplified with more-open chords, shredded by hyper-amplified distortion, and abandoned altogether in improvised bridges featuring Brownstein’s acidic leads. Her unbounded runs often match Tucker’s pitching her huge voice to new heights of keening. Yet those runs are also raw and instinctive, marking her first serious foray away from the taut, angular riffs that she mastered on Sleater-Kinney’s twin riot-grrrl-era peaks, Call the Doctor (Chainsaw, 1996) and Dig Me Out (Kill Rock Stars, 1997).

"You know, we’ve already made Dig Me Out, and I love that record, but we couldn’t really make it again," she says. "I mean, one thing I like about the new songs is that there are moments for improvisation where we don’t know what’s going to happen. Just to feel like you’re writing from a cliff ledge, or something, where you feel like your footing is a little unstable for a while. And you might slip from it. Or you might be able to pull yourself back up to safety, but in that moment of not being sure, you might do something that’s really graceful or really exciting. To me, that kind of music is much more reflective of the time we’re living in. It has more chaos in it, and it has moments of surprise, and moments of unease."

For some old fans, those moments in The Woods have been difficult to assimilate, but for others, especially those who share the band’s progressive politics, they make instant sense. "We left to record the album I think two days after the election, and so that did actually go into our mind frame." Yet if the Republican sweep sealed the deal, this mind frame wasn’t about facing just "the caprices of the political sphere that no one can make sense of," as Brownstein puts it, but also all the "internal and external landscapes that are prickly and dark and unsettling."

That confrontation has been a part of Sleater-Kinney’s music since the days when Tucker and Brownstein were romantic as well as musical partners. It reached a new intensity on "Sympathy," which closed 2002’s One Beat (Kill Rock Stars), addressing the grimmest moment of Tucker’s life, right after the birth of her baby. "Marshall, he was really premature," Weiss told me back then. "And there were some moments where it wasn’t for sure whether he was going to make it or not. Things turned out okay, but it also has the darkness of knowing that this kind of pain exists. Her [Tucker’s] performance on that song is really amazing. When she sings that part in the middle, it’s so sad and so scary at the same time. That was an incredible moment of recording that I don’t think I’ll ever forget."

Brownstein now says, "We wanted to take that moment in ‘Sympathy,’ that moment where it breaks down into where Corin’s reaching this emotional pitch of the song. The Woods was just about those moments happening more often." Not that it was easy to reach them. In the months following One Beat, the band wrote a whole set of songs, then scrapped them as Tucker composed two numbers that became the new disc’s cornerstones. "Entertain" is an indictment of popular culture that draws on, I suspect, everything from the trio’s experiences opening on Pearl Jam’s last tour, when both bands were on occasion booed as they spoke out against the Iraq War, to Brownstein’s frustrating foray into academe in 2004, when she attended California-Berkeley for six months. "Let’s Call It Love" is an 11-minute blowout that leaves classic punk in the dust as it explores the limits of desire. The song is Tucker’s, but as Brownstein explains, "Janet and I pushed her so hard on that chorus, she was singing something really melodic and pretty. We stopped in our practice space and we almost got in a fight. And she was so mad at us that the next time we got to that part of the song, she was just screaming her head off, and it was just this dark and guttural place, and I turned around and she was bright red; I could tell that she was really mad at us. And then we heard the song, and we were like, ‘That’s perfect!’ There’s a lot of that on this record, of pushing each other to the brink."

Even the straightforward rabble rouser "What’s Mine Is Yours" reflects that mind set. The song "goes along in a fairly familiar way," Brownstein explains, "and then it’s completely destroyed in the middle, and you sort of wonder, ‘How are we going to get back?’ Like, here we are now, in this total wilderness of a song, there’s no familiarity to it anymore, and then it veers off in a totally different uncertain direction, and eventually, barely, makes it back to the first part of the song. To me, a lot of the lyrics on this record are about that very journey and trying to figure out, like, well maybe it’s okay not to know the answers, but how do we live in a world where we don’t know answers? How do you find any peace in that? Or how do you finally get back?"

They already know one answer. When you can only expect the unexpected, you answer with the same. If I were Brownstein’s dog, I’d watch my back.